This application is a national stage application under 35 U.S.C. § 371 of International Application No. PCT/EP2016/062134 filed 30 May 2016, which claims priority to EP Application No. 15172382.2 filed 16 Jun. 2015, the disclosures of which are expressly incorporated herein by reference.
In crop protection, in pesticides and also in the industrial non-crop sector, the biological efficacy of such pesticides or pesticide mixtures is frequently improved by using what are called adjuvants or else auxiliaries or additives. Efficacy is frequently also referred to as effectiveness. The Pesticides Safety Directorate (PSD, the executive branch of the Health and Safety Executive (HSE), a non-governmental public organization in Great Britain) defines an adjuvant as a substance other than water which is not itself pesticidally active but increases the effectiveness of a pesticide. (http://www.pesticides.gov.uk/guidance/industries/pesticides/topics/pesticide-approvals/legislation/adjuvants-an-introduction). These are either added to the aqueous spray liquor shortly before deployment and spray application (as tankmix additive) or incorporated directly into crop protection composition formulations. With regard to the use of the word adjuvant, patents or the literature often use the terms surfactant or wetting agent synonymously, but these are much too wide-ranging and can therefore be interpreted as more of an umbrella term. Because of the use envisaged here, the term “adjuvant” is employed.
In practice, there are numerous crop protection active ingredients which achieve acceptable effectiveness, i.e. practically relevant efficacy, only with the aid of adjuvants. The adjuvants help here to compensate for the weaknesses of the active ingredient, for example the UV sensitivity of avermectins (destroyed by ultraviolet radiation) or the water instability of sulphonylureas. More recent active ingredients are generally water-insoluble and, in order therefore to be able to spread effectively over a target=target organism=plant, adjuvants are indispensable for the aqueous spray liquor, in order to compensate for the poor wetting of surfaces by way of a physical influence on the aqueous solutions. In addition, adjuvants help to overcome technical application problems, such as low water application rates, different water qualities and the trend to increased application rates. The increase in pesticide efficacy and the compensation for weaknesses in the crop protection compositions by adjuvants are generally referred to as increasing the activity or enhancing the effect of the crop protection composition application.
In crop protection, in pest control and in the industrial sector, chemical or biological crop protection compositions (also called pesticides hereinafter) or pesticide mixtures are employed. These may be, for example, herbicides, fungicides, insecticides, growth regulators, molluscicides, bactericides, virucides, micronutrients and biological crop protection compositions based on natural products or living or processed microorganisms. Active pesticidal ingredients are listed in connection with their fields of use, for example, in ‘The Pesticide Manual’, 14th edition, 2006, The British Crop Protection Council; biological active ingredients are specified in ‘The Manual of Biocontrol Agents’, 2001, The British Crop Protection Council. “Pesticide” is always used as a collective term hereinafter.
In order to be able to assess the agricultural potential and the activities of substances, it is necessary to carry out not only the laboratory and greenhouse experiments, but also realistic applications in agriculture, for example field trials.
In practice, crop protection compositions of this kind are often added to a tank with water as an ingredient and distributed in what is called the spray liquor with gentle stirring, in order to dilute the concentrated formulation of the active ingredient prior to spraying and to make it tolerable for the plants. Adjuvants are either incorporated into the crop protection formulation here prior to the tankmixing operation or added to the spray liquor as separate tankmix additives.
Adjuvants used are frequently synthetic surfactants, for example ethoxylated alcohols or alkyl polyglycosides. The use of water-soluble hydrophilic polyglyceryl esters as adjuvants in crop protection formulations is likewise known (WO 2002/034051, US 2006/0264330A1). In general, a feature common to these adjuvants is that they are water-soluble hydrophilic substances. Further adjuvants frequently used are additionally alkoxylated trisiloxane surfactants which lower the static surface tension of spray liquors or water to a greater degree than the organic surfactants used in the past, for example nonylphenol ethoxylates. Trisiloxane surfactants have the general structure Me3SiO—SiMeR—OSiMe3 where the R radical is a polyether radical. The use of superspreading trisiloxane surfactants, for example, BREAK-THRU® S-240, Evonik Industries AG, in combination with a pesticide, leads to an improvement in pesticide uptake by the plant and generally to a rise in the efficacy or effectiveness thereof. U.S. Pat. No. 6,734,141 states that this increase in effectiveness is occasioned specifically by a low surface tension and not necessarily by the spreading. The term “surface tension” is understood in the prior art to mean static surface tension. In the case of trisiloxanes, for example, static surface tension is about 20 to 25 mN/m.
WO1994022311 discloses superspreading compositions comprising polyether-modified siloxanes which may have two groups of polyethers: firstly polyethers having exclusively oxyethylene groups, and secondly polyethers which, in addition to oxyethylene groups, may also have oxypropylene groups. Experimental data are disclosed for modified siloxanes wherein the polyether residue contains exclusively oxyethylene groups. These are known, for example, as SILWET L-77.
A disadvantage of the prior art is that none of the superspreading trisiloxanes are biodegradable. For environmental reasons in particular, ever greater value is being placed on environmentally friendly products, particularly in order to gain popular acceptance with respect to chemical products in agriculture.
“Superspreading” in the context of the present invention is understood to mean that a 0.1 percent by weight solution in water, after examination in accordance with ASTM E2044-99 (2012), has a diameter of spread of at least 35 mm. Preferably, a droplet of a 0.1 percent by weight solution in water having a volume of 50 μm on a polypropylene film spreads to an area of at least 10 cm2. Preferably, the spread is examined at 25° C.; preferably, the spread is determined at a relative air humidity of 60% and a pressure of 1013 mbar.
“Readily biodegradable” within the scope of the present invention describes degradability according to OECD Method 301F CD, preferably as described in the examples.